Engenharia Química

In this study, a total of 20 elements (essential, non-essential and toxic): lithium (Li), sodium (Na), potassium (K), gallium (Ga), magnesium (Mg), zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), vanadium (V), chromium (Cr), nickel (Ni), cobalt (Co), molybdenum (Mo), selenium (Se), barium (Ba), tin (Sn), arsenic (As), lead (Pb) cadmium (Cd) and mercury (Hg) in natural and cultured Cordyceps kyushuensis have been determined by means of inductively coupled plasma mass spectrometry (ICP-MS). Cultured stroma, natural stroma and natural worm were digested by microwave-assisted method before analysis. The proposed ICP-MS method was validated by analyzing a certified reference material (CRM) GBW10015 (spinach). The results of one-way analysis of variance (ANOVA) revealed that the element concentrations in the three kinds of samples were significantly different (p < 0.05). Except for Mg, Zn, Cu, the values of other elemental contents were the highest in the stroma of natural C. kyushuensis. In comparison with the worm, the concentrations of determined elements in wild stroma were higher. The remarkable difference of elemental contents between cultured and natural stroma may be caused by distinct growing environment. This finding highlighted the usefulness of ICP-MS elemental analysis and enhanced the value of C. kyushuensis as a candidate for nourishing food based on its composition.

This investigation focused on the validation o f the methodology used in determining the presence of specific elements in human blood. Concentrations of macro-and micronutrients in umbilical b lood (UCB) samples fro m 37 lactating volunteers who gave birth in the city of Taubaté , State of Sã o Paulo, Brazil. The determinations of Ca and Mg were carried out in a flame ato mic absorption spectrometer (FAAS) and those of Cr and Mn in a graphite furnace ato mic absorption spectrometer (GFAAS). A procedure for preparing samples was optimized and evaluated. Standard addition methods and determinations by ICP OES were used to validate the analytical procedures. An acetylene/air mixture was optimized at 2.0/17.0 L min-1 (Ca and Mg). Pyrolysis and atomizat ion temperatures for Cr were at 1400°C and 2100°C, respectively, for Mn at 1300°C and 1700°C, respectively. The most efficient chemical modifier was a solution containing 5 g of Pd + 3  g of Mg(NO3)2. Characteristic masses for Cr and Mn were 2.6 and 2.7 pg, respectively. The methods presented high analytical efficiency in the determination of Ca, Cr, Mg and Mn (recovery fro m 98.68% to 108.22 %). M inimal data variations in repeatability and reproducibility indicated significient precision and accuracy for the proposed methodology. The placenta did not block transport of elements fro m mother to fetus. The contents of the elements analyzed in the UCB were co mpared to those detected in maternal blood (M B). Most of the children exh ibited normal weight (fro m 2.5 to 3.0 kg) as per the Brazilian Min istry of Health standards. Such results indicate that the levels of concentrations of the elements in the UCB did not affect the weights of the neonates. activity is also reduced . These characteristics in neonates facilitate a h igher potential fo r the absorption of elements in contrast with adults. This greater absorption capacity is also applicable for various toxic elements .

The combined use of internal standardization with collision and reaction interface in an inductively coupled plasma quadrupole mass spectrometer (ICP-QMS-CRI) was evaluated. The behavior of several elements (Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Pb, Sb, V and Zn) was studied by introducing H 2 or He through the skimmer and sampler cones of the CRI device and by using In, Rh and Sc as internal standards. Certified reference material of trace elements in water (NIST 1643e) was used to evaluate the performance of the method. A vinegar sample and mixed food diet standard reference material were directly introduced into the equipment as complex matrices for Cr and V determinations. Improvements in accuracy and precision were attained combining both strategies. The introduction of H 2 through the skimmer cone was the best way to overcome polyatomic ions formation and to improve SBR and BEC values for several elements. The use of Sc as internal standard improved the performance of ICP-QMS-CRI.

AVALIAÇÃO DA METODOLOGIA 5220 D. CloseD Reflux, ColoRimetRiC methoD PARA DETERMINAÇÃO DA DEMANDA QUÍMICA DE OXIGÊNIO (DQO) EM EFLUENTE LÁCTEO RESUMO A demanda química de oxigênio (DQO) é amplamente utilizado como indicador e medida da biodisponibilidade do carbono em águas. DQO é definida como a quantidade equivalente consumida na oxidação química da matéria orgânica por um forte agente oxidante. Recentes trabalhos sobre DQO relatam sobre interferências e sinergismos que influenciam a resposta; porém pouco se discute sobre a validade, calibração e faixas de linearidade dos métodos empregados. No presente trabalho fez-se a otimização de metodologias espectrofotométricas para determinação de DQO, em duas diferentes faixas de concentrações (200 e 2000 mg O 2 L -1 , respectivamente baixo e alto teor), por análises comparativas. Através de análises estatísticas obtiveram-se valores de repetibilidade e reprodutibilidade de 3,75% e 9,01% e de 3,56% e 8,55%, para DQO com baixo e alto teores, respectivamente.

In the present work was analyzed qualitatively and quantitatively waste from factories industrial district Cunha Porã - SC, as well as a check of waste management plans for each factory. Through interviews with the technical managers of each factory was possible to classify the waste as required by NBR 10004/2004. It is found that all the studied company has management systems. Management systems more employees are based on 3R’s and Cleaner Production (CP) strategies, mainly. It was observed the largest generation of class II residue (80.33%) than Class I hazardous waste (19.67%). Since the waste class IIA represents 80.9%, it greater quantity than waste Class IIB that represents 19.1% of the total generated relating to Class II. At the same time it was verified that the residues were intended for recycling and reuse. Thus it is concluded that the companies had strict control over the waste generated by working in na environmentally sustainable way and within which recommends NBR 10...

This study aimed to evaluate the efficiency of Photo-Fenton and Fenton processes in reducing organic matter of dairy effluent. An Orthogonal Array L9 Taguchi was used to determine optimal conditions of acidity media, temperature, Fenton concentration and UV radiation intensity. Reaction time was set up to 60 min. Optimized parameters were: pH 3.0, temperature, Fenton reagent concentration and UV radiation at the highest level. The Dissolved Organic Carbon percentage reduction (DOC) was 91 %. An effective degradation study was carried out, in which, the reduction percentage was found to be less than the most efficient DOC removal. A cost/benefit evaluation of the AOP process employed on the in natura dairy effluent treatment showed that the reagent consumption the main cost of the process. The highest efficiency experiment for the dairy effluent of this study had operational costs lower than US$ 0.50 to Photo-Fenton and Fenton processes, respectively.

This work evaluated the efficiency and systemic application of heterogeneous photocatalytic degradation for dairy wastewater under advanced oxidation process (AOP) utilizing solar radiation and immobilized ZnO as measured by total organic carbon (TOC). The AOP system consisted of a semibatch reactor and glass tank operated with an initial volume of 3 L of dairy wastewater. ZnO was immobilized on a metal plate of 800 × 250 mm and used as a catalyst bed. Evaporation rate was considered when effective degradation of the photocatalytic system was determined. The AOP utilized Taguchi's L 8 orthogonal array. The entry variables were pH, reaction time, initial organic load in the effluent, and ZnO coating thickness on the catalyst bed. When optimized, an effective TOC degradation of 14.23% was obtained under variable values of pH 8.0, a metal-plate coating of 100 micrometers (µm) ZnO, and total reaction time of 180 min.